&DRIFT: MINIMISE
The function to be minimised has to depend on at least one of
the following variables:
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Symbol meaning
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TIME total drift time [micro seconds]
LENGTH length of the drift line [cm]
DIFFUSION integrated diffusion coefficient [cm]
AVALANCHE integrated and exponentiated Townsend coefficient
LOSS integrated and exponentiated attachment coefficient
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The default function to be minimised is TIME.
This function should return either TRUE or FALSE. If FALSE is
returned, then the point will not be considered anymore during
the minimisation process.
The following variables can be used:
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Symbol Meaning
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TIME total drift time [micro seconds]
LENGTH length of the drift line [cm]
DIFFUSION integrated diffusion coefficient [cm]
AVALANCHE integrated and exponentiated Townsend coefficient
LOSS integrated and exponentiated attachment coefficient
STATUS a string variable which can take the values:
"Left_Area", "Too_Many_Steps", "Abandoned",
"Hit_Plane", "Left_Drift_Medium", "Left_Mesh",
"Hit_X_Wire" and "Hit_X_Replica". "X" is the label that
you have assigned to the wire. Case is significant.
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The default selection curve returns always TRUE.
ON should be followed be a parametrisation in terms of the
variable T of the curve over which teh minimisation should
take place.
The range of T can be specified via RANGE.
No default curve is provided.
RANGE should be followed by the minimum and the maximum value
the variable T is allowed to take during minimisation, see
ON for further information on T.
No default RANGE is provided.
The number of points on the curve for the initial scan of the
curve.
The default value for N is 20.
Requests that the minimisation be carried out for electrons.
This is the default.
Requests that the minimisation be carried out for ions.
By default, minimisation is done for electrons.
Requests that the minimisation be carried out for positively charged
electrons or ions.
The default is NEGATIVE.
Requests that the minimisation be carried out for negatively charged
electrons or ions.
This is the default.
The procedure assumes it has converged if the relative change in
function value has dropped below eps_f.
The default value is 10E-4, which is also the smallest reasonable
value on computers like Vax and IBM. On Cray and other computers
with 64 bit precision, eps_f can be made smaller.
The procedure assumes it has converged if the relative change in
position of the minimum has dropped below eps_pos.
The default value is 10E-4, which is also the smallest reasonable
value on computers like Vax and IBM. On Cray and other computers
with 64 bit precision, eps_pos can be made smaller.
The maximum number of iteration steps during the minimisation
process.
By default 20.
Requests some printout during the minimisation procedure.
This is default.
Requests dataset output of the minimisation results.
No such output is produced by default.
Keyword index.
Formatted on 10/11/98.